Alcaloides indólicos das partes aéreas de psychotria sp.(rubiaceae) e síntese de tiohidantoínas e tioureias derivadas de aminoácidos e do r-(+)-limoneno

• Ano de defesa: 2013
• Autor(a) principal: Moraes, Aline Pereira
• Orientador(a): Oliveira , Cecília Maria Alves de
• Banca de defesa: Oliveira, Cecília Maria Alves de, Fátima, Angelo de, Queiroz Jùnior, Luiz Henrique Keng
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Química (IQ)
• Departamento: Instituto de Química - IQ (RG)
• País: Brasil
• Palavras-chave em Português: Psychotria; Alcaloides indólicos; Tioureias; Tiohidantoínas
• Palavras-chave em Inglês: Psychotria; Indole alkaloids; Thioureas; Thiohydantoins
• Área do conhecimento CNPq: QUIMICA::QUIMICA INORGANICA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/3316

The use of natural products and their synthetic derivatives has been a relevant strategy in the development of novel medicines. Phytochemical studies and synthesis of natural-product-based libraries are primordial in the search for therapeutic agents. Previous phytochemical studies of genus Psychotria (Rubiaceae) have resulted in the identification of polypyrrolidine indole and monoterpenoid indole alkaloids, which present a broad range of biological activities, such as antifungal and inhibition of monoamine oxidases (MAOs) A e B, that are related to neurodegenerative diseases. This study aims to evaluate the phytochemical composition of the aerial parts of Psychotria sp. collected in Brazilian Cerrado. Fractionation of the crude extract by column chromatography on silica gel and Sephadex led to isolation of three known indole alkaloids: bahienoside A, desoxycordifoline and desoxycordifolinic acid. Additionally, thiohydantoins and thioureas were synthesized from amino acids and R- (+)-limonene, in order to assess the cooperative effect of indole nucleus combined with terpene, thiourea and thiohydantoin units. Preliminary tests showed that desoxycordifoline, hydantoin (20) and thiohydantoin necrostatin-1 (14) inhibit the enzyme MAO-A higher than 80% at concentrations of 175 mM, 100 mM, 386 mM, respectively. Also, the polar extracts of the leaves of Psychotria sp. showed antioxidant activity with IC50 < 50 mg.mL-1 measured by DPPH free radical scavenging assay.